Why India does not try for POK?

What is the reason that India does not try to annex the part of Kashmir controlled by Pakistan?

The time for India to get back PoK (Pakistan Occupied Kashmir as it called in India or Azad Kashmir as it is called in Pakistan) is long past. 

Why can't India win back PoK?

1. Jawaharlal Nehru prematurely went to the UN Security Council in 1948 that brought external intervention to the dispute. India is still paying for many of the mistakes of our first Prime Minister. Once the UN got involved, it became hard for India to take aggressive action there.https://www.mtholyoke.edu/acad/i...(This article will show India's advantageous position before Nehru's intervention brought a ceasefire. http://en.wikipedia.org/wiki/Fir... )
   
   
2. After 1970s, both nations developed nuclear and missile capabilities precluding the possibility of a major war. If India were to attack PoK, Pakistan is guaranteed to respond with a nuclear attack.
3. Currently, Gilgit-Baltistan and Pakistan Administered Kashmir (PoK) are almost entirely Muslim (after the minority Hindus were driven out or got killed in partition in 1947) and India will find it hard to argue its case of winning back. If anything, India could have fought to keep Sindh (that had the largest Hindu percentage among Pakistani provinces in 1947) rather than Kashmir.
4. Finally, status quo is beneficial to everybody (even if Pakistan makes noise otherwise). Ending the current status can open Pandora's box.